I'd go further and say the prop should fail to 'auto feather' position at all times.
At first glance this might seem desirable, but the problem with this is that if there was a short power loss for a few seconds, such as running a tank dry in the cruise, the prop would feather, and stop rotating. This would leave you with a stopped, rather than windmilling enging, which may be impossible to re-start after changing tanks.
You would not want a prop going to coarse pitch after a failure, as there is still lots of drag from a coarse prop, and then that drag would increase once you went to feather. The plane will be hard to handle in this configuration, so anything that prolongs that is worse.
The drag of a windmilling prop reduces as the pitch becomes coarser, reducing to min. drag as the prop reaches the max. coarse position, Ie. feathered.
MJ
